The invention relates to control apparatus and method for adjusting a transmission throughput of a data communication through a communication network and, more particularly, to control apparatus and method for adjusting a transmission throughput in a data communication through a communication network of a frame relay/protocol.
in recent years, the development of a communication technique for realizing a data communication by connecting electronic computers or the like through a communication network is remarkable. A new protocol of a high efficiency and a high performance has been developed.
In the conventional communication network, there are a network such as an exclusive-use line or a line exchange network in which the communication performance is fixed and a network such as a packet exchange network like a DDX or an ISDN in which although a communication capacity and a performance change, a data dropout hardly occurs due to a flow control. Namely, in the packet exchange network like a DDX or an ISDN, a communication connection is established between a transmission terminal and a reception terminal by selectively connecting relay points in a communication network, and an error detection correction control and a flow control are executed every data communication between the relay points.
However, in the data communication using the packet exchange network such as DDX or ISDN in which the error detection correction control and flow control are executed, a communication throughput as an actual communication performance is extremely low for a physical communication speed of a communication line due to those control loads. For example, although the maximum physical speed of the DDX is equal to 48 kbps, the actual communication throughput is reduced to about 9600 bps. Although the physical speed of the ISDN is equal to 64 kbps, on the other hand, the actual communication throughput is reduced to about 9600 bps.
There is a frame relay/protocol as a new protocol of a high efficiency and a high performance to solve such a problem of the communication network having the error detection correction control and flow control and to realize a high speed communication. According to the frame relay, although the communication capacity and performance change like a digital packet switching network of the DDX, ISDN, or the like, the network doesn't have the error detection correction control and flow control. Therefore, the control load of the network is low and the high speed exchanging process can be performed. So long as the network is free, a real speed near the maximum physical speed can be obtained and a data communication of a high efficiency and a high performance can be performed.
However, according to the communication network using the frame relay/protocol, although the communication capacity and performance change like the digital packet switching network, since the network doesn't have the error detection correction control and flow control, there are drawbacks such that if the electronic computers or the like connected to the network don't grasp a vergence state of the network and promptly change a transmission throughput, a data dropout easily occurs and a retry of the protocol between the electronic computers or the like connected to the network frequently occurs, so that the communication performance deteriorates.